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1、BasedonmonolithicintegratedcircuitautomobilesecurityalarmsystemdesignAbstractjDecodestheautomobilesecuritysystemusingthemonlitchisintegratedcircuitinteriorresourcesrealizationjumpcode,iteachtimeusestheremotecontrolpasswordallischanging,bothenhancedthesystemsecurity,andgreatlyreducedthecost.KeywrOrdj
2、Monolithicintegratedcircuit,Automobilesecuritysystem,Code/decodeIntroductionIsunceasinglyprogressivealongwiththesocialeconomyandthehightechrapiddevelopment,intheroutineworkandthelife,theautomobilehasbecomethepeopleidealtransportationvehicle.Butthefollowingmotorvehiclethecasewhichrobbedgraduallyisals
3、oincreasedhascreatedthepiloteconomicalpropertyloss.Inordertoreducetheautomobiletorobtheeventtheformationrate,forhastheautomobiletheusertoprovidethesafetycontrol,simplydevelopsonekindtobereliable,theeaseofoperation,cansendoutinthediscoverynormalconditiontothepilotreportstothepolicethereminderandthese
4、curitywarningsafetysystemhasthepracticalsignificance.Thisarticlebasedontotheexistingautomobilesecurityalarmsystemgeneralizedanalysis,developsonekindofbrand-newsecurityalarmsystem.Thissystemhasmainlyusedthejumpcodecode/decodingprinciple,causestheoverallsystemtobesafer,greatlyreducespasswordexplaining
5、rate.1.SystemprincipleofworkTheautomobilesecurityalarmsystemtheremotecontrolwhichcarriesbythedriverandinstallsintheautomobilethecontrollertwopartscomposes.TheremotecontrolandthecontrolleralluseeightCMOSwhichAmericanAT-MELCorporationproducestheAVRmonolithicintegratedcircuit,thisseriesmonolithicintegr
6、atedcircuitbasedonnewsimplifiesinstructionRtheISCstructure,includestheservicelifemosttobefewis1,000timewrites/scratchesthecirculationtheFlashprogrammemory,aswellastheservicelifeatleastis100,OOOtimewrites/scratchesthecirculationEtheEPROMdata-carrierstorage,some2onlyhavewhentheentirepiececleaningcancl
7、eanIheprogrammingencryptionlocksthelocalization.1.lSystemdesignTheautomobilesecurityexaminationusestheultrasonicsensor.Theultrasonicsensoriscomposedbytheultrasonicwavetransmissioncircuitandthesupersonicreceptionelectriccircuit,intheautomobilecabappropriateposition,installstheultrasonicWaveIaunchZrec
8、eiver,aswellasswitchelectriccircuitTl.Whentheautomobileparksthevehicleownerpersonmustleavetheautomobile,withremotecontrolclosedswitchTl,theautomobilealarmsystemsatgarrisonsthecondition,aroundthesystemuseultrasonicwaveexaminationvehicleobstacle.Launchesthepartialelectriccircuitslikeschart1toshow.When
9、itsPlmouthPl.1,Pl.2totheDtrig,thePLOcontrolultrasonicwavelaunch,are0,thehotoelectricitycoupleroutputstheTPlendis1,thepermissionultrasonicwavelaunch,launches/thereceiveultrasonicwaveinturn,thecirculationrepeatedlycarrieson.Simultaneouslythemonolithicintegratedcircuitinteriorcounterstartstocount.Thest
10、eamdistancebetweenvehiclesobstacledistanceisthetimewhichsendsoutthroughthesoundnavigationandrangingreflectsspendsdeterminesandcarriesonthecomputation.ThereflectionsignalcausestheDtriggertoproduceinterruptrequestsignalINTl,simultaneouslystopscounting,readstakescountsthevalue,calculatestheactualdistan
11、ceaftertheformula,thencarriesonthecomparisonwiththedatumdistance,ifexamineswhentheactualdistanceisbiggerthanreferencevalue80Crn,doesnotcarryontheaccustom-opticstoreporttothepolice;IfsomepeopleapproachIheautomobiletoenterthecab,theexaminationactualdistanceissmallerthanorwasequaltowhenreferencevalue80
12、cm,throughmonolithicintegratedcircuitP2.2andtheP2.3port,actuatestheindicatinglampdisplaycircuitandthesoundalarmcircuit,sendsoutthreetwoflash.Andtriggersahighlevel,theactuationiswirelesssignaltransmissioncircuit.Chart!Ultrasonicwavetransmissioncircuit1.2CodeZdecodingprincipleThepresentautomobileremot
13、econtrolsecuritysystemaremanyisusesVD502627,PT226272,HT12EDandsoonthegeneralcode/decodestheelectriccircuit,itspassworddecidedbythecomponentaddress,eachsetofsecuritysystemsuseafixedinvariablepassword.Alongwiththemicroprocessingtechnologydevelopment,throughthereceiveremotecontroltransmittingmessage,ma
14、yinterceptthisfixedpassword,moreovergeneralarrangesthedecodingaddresstolosethepersontocarrythecomponentsizelimit,itsquantityisimpossibletoomuch,canobtainnotrepeatedlycclesveryisalsolimited,alsocanveryquicklyexplainthepasswordwiththeautomaticScannerTherefbre,thiskindofpasswordfixedinvariableautomobil
15、esecuritysystemhasreceivedtheseriousthreat.Decodestheautomobilesecuritysystemusingthemonolithicintegratedcircuitinteriorresourcesrealizationjumpcode,iteachtimeusestheremotecontrolpasswordallischanging,withthepasswordnolongerduplicatesuses,causestheinterceptionpasswordalsoismakesafutileeffort,inaddit
16、ion,itmayincreasetheenoughmanypasswordsfigure,enhancesthesystemresistanceillegalscanningtheability.Theremotecontrolcodingaltogetherhas12bytes,separatelyby3bytescodeschannelscode,3bytescodesforewordsnumber,5bytesjumpscodes,1bytepressedkeyoperationcodeiscomposed.EncodedfrontaddsonIogicineachbyteOtotak
17、etheoutsetposition,encodedbehindaddsonalogical1achievementineachbytetostoptheposition,andinmostfrontaddsonseverallogic1totaketheguidancesignal,Ihisconstitutedtheserialcodedsignalwhichusesintotransmit.Thecodechannelcodeusesintoexpresstheremotecontrolstatus;eachsetofsystemsuseafixedchannelcode.Thecode
18、forewordnumberusesintorecordtheencodedorder,itsstartingvalueisO,themonolithicintegratedcircuiteverytimecodesatime,thecodeforewordnumberupwardlycountstime.ThecodechannelcodeandthecodeforewordnumberdepositsinmonolithicintegratedcircuitEEPROM,guaranteesthempowercuttheinfluence.Thejumpcodeisthesystemati
19、ctruepassword,itpassesthroughthecomplexspecialalgorithmbythecodechannelcodeandthecodeforewordnumbertoextract,thisspecialalgorithmforeignsecurity.Thepressedkeyoperationcodebythepressedkeywhichpresseswasdecided,whenthehypothesisthekeyispresseddown,itscodedecidesasO1H;Whenrelievesuthekeypressesdown,its
20、codedecidesasOOH.WhetheristhedecodingconfinnsreceivethecodelegitimateaseriesOfoperatingprocess.WasconfirmedthelegitimatecodeneedstoSatisfythreeconditions;(1)codesthechannelcodeandthedecodingchannelcodeissame;(2)codedtheforewordnumbertobebiggerthanthedecodingforewordnumber(decodingforewordnumbertorec
21、ordOnlegitimatelyhasusedcodeforewordnumber,thisconditionmightguaranteebeforehasusedcodewasinvalid);(3)jumpsthecodetobeequaltoreusesthespecialalgorithmtoextractchangesthecode.Afterthemonolithicintegratedcircuitconfirmedreceivesisthelegitimatecode,writesthecodeforewordnumberinthedecodingforewordnumber
22、,andcompletescorrespondingoperationprocessingaccordingtotheoperationcode.ThedecodingchannelcodeandthedecodingforewordnumberalsodepositsinmonolithicIntegratedcircuitEEPROM,guardsagainstbecauseofpowercutloses.13SecurityreportstothepolicerealizationIfwillhaverobberChenZheRutheroom,startstheautomobile,a
23、fterwrongpassword,thentheautomobilestoragebattery+I2Vvoltage,theignitionelectriccurrentwayignitionlock,theignitionoutage,theengineextinguishes,againstarts,willduplicatetheaboveprocess,likethis,thebanditsandthievesalwayswillnotbeabletoStarttheautomobile,willnotbeabletoachieveitsanticipatedgoal.Theala
24、rmcircuitmainlyiscomposedbytheintegratedblockandthespeakerandelectronicswitchingSCR.Triodeorthemultiple-unittube,areforenhancetheelectriccircuitmeasurewhichthepowerbutoftenuses,ithascomposedacurrentamplificationfactorverybigequivalenttransistor,totalenlargementfactorforthesetwoenlargementfactorprodu
25、ct.SCRistheelectronicswitchingWhichconstitutesbytheSilicon-controlledrectifier,theelectriccapacityandtheresistanceconstitutionnegativeboosterconcurrentlyfilter,provides+3+4VtoICthevoltage,ICistracesDrawsupsoundreportstothepolicetheintegratedcircuit,thealarmapparatusbytheSCRConlroIJObSthevehiclethief
26、onceafterthewrongpassword,thenthestoragebatteryelectriccurrententersthesecuritysystembesidesagroup,anothergroupisstartedintheengine,afterleadstheenginework,naturalcontactoutputvoltage,afterthedifferentiatingcircuit,Silicon-controlledrectifierSCRistriggered,alsopassesthroughIheresistancetofallthepres
27、sure,thevoltageaddsintheICpowersourceinputend,ICobtainsthevoltageoutputalarm,enlargesafterthemultiple-unittube.DestroysmovesthespeakertosendOutresoundinglyreportstothepolicethesound,whenstaticstate,entireelectriccircuitdoesnotconsumetheelectricity.2SoftwaredesignThealarmapparatussoftwaredesignmainly
28、dividesintorMasterroutine(alarmapparatusinitialization,keymodulationanddecoding);Alarmapparatusinterrupthandlingroutine.Thisalarmapparatusinstallsontheautomobilesteeringwheel.Afterinstalls,startsthealarmapparatus,thealarmapparatusautomaticallyretards2O-3Ostostarttowork,inordertoletsusethepersontohav
29、etheenoughtimetolockthegatetoleavetheautomobile.Afterthetimedelaythealanapparatusentersthevaluetodefendtheactivestatus,oncethevehicledooristurnedonorthewindowpanehitsgarrulously,theoscillationpick-upexaminesthesignal,timedelay20sstartstoreporttothepolice.Thetimedelaygoalisthemasterwhichcausestheauto
30、mobileisopeningthegatetoenterthevehicleinternalenergyclosurealarmapparatus,inordertoavoidreportstoIhepolicebymistake.2.1 MasterroutineThispartmainlycompletestoeachseveranceentrancehypothesis,andreportstothepolicethedepositingunitinitializationtoeachfixedunit,establishesthespecialsymbolvalueandtothep
31、ressedkeyinterruptsprocessing.Masterroutinedesigndiagramlikechart2shows.Chart2masterroutineframechart22AlarmapparatusinterrupthandlingroutineTheburglaralarmdisposalprocedureusestimeseveranceinquiryprocessing,eachtimeseverance,onlyisinquireseachkindofcontrolflagbit,controlseachgroupoutputaccordingtoi
32、tscondition.Theprocedurehasnotusedhascirculationprocessingtheway,thereforetimecontrolconclusion,cannoteliminatecontrolstheflagbil,onlyisrepositionsthescene,thewaitingnexttimeseverance,againjudgeswhethercontrolstheconclusion.3ConcludingremarkUsesautomobilesecurityalarmsystemcostwhichthiskindOfmonolit
33、hicintegratedcircuitcomposeslow,ferformancereliable,simultaneouslysettlestheextensiontobeconvenient.Theusejumpcodecode/decodingprinciple,causesthesystemtobesafer,greatlyreducespasswordexplainingrate,willobtaintheWidespreadapplicationinthefutureautomobilesecurityalarmsystem.基于单片机的汽车防盗报警系统设计摘要：应用单片机内部
34、资源实现的跳变编码/解码汽车防盗系统，它每次使用的遥控密码都在变化，既提高了系统的平安性，又大大降低了本钱。关键词:单片机汽车防盗系统编码/解码引盲随着社会经济的不断进步和高科技的飞速开展，在日常工作和生活中，汽车已成为人们理想的交通工具。但随之而来的机动车辆被盗的案件也逐渐增多，造成了驾驶员经济财产的损失。为了减少汽车被盗事件的发生率，给拥有汽车的用户提供平安保障，研制一种简单可靠、操作方便，能在发现不正常情况下给驾驶员发出报警提醒和防盗警报的平安系统具有实际意义。本文基于对现有汽车防盗报警系统的综合分析，开发出一种全新的防盗报警系统。该系统主要使用了跳变码的编码/解码原理，使得整个系统更加
35、平安，大大降低密码破解率。1.系统工作原理汽车防盗报警系统由司机携带的遥控器和安装在汽车内的控制器两局部组成。遥控器和控制器都用美国AT-MEL公司生产的八位CMoS型AVR单片机，该系列单片机基于新的精简指令RISC结构，含有使用寿命最少为100O次写/擦循环的Flash程序存储器，以及使用寿命至少为10万次写/擦循环的EEPRoM数据存储器，有2位只有在整片擦除时才能擦除的编程加密锁定位。1.1 总体设计汽车防盗的检测,采用超声波传感器。超声波传感器由超声波发射电路和超声波接收电路组成，在汽车驾驶室的适当位置，装设超声波发射/接收器，以及遥控开关电路T1。当汽车停放车主人要离开汽车时，用遥
36、控器闭合开关Tl,汽车报警系统处于设防状态，系统利用超声波检测车周围的障碍物。发射局部电路如图1所示。它的Pl口的P1.LPL2对D触发器初始化，P1.0控制超声波发射，为0时，光电耦合器输出TPl端为1,允许超声波发射，依次发射/接收超声波，循环反复进行。同时单片机内部的计数器开始计数。汽车距障碍物的距离是通过声纳发出到反射回来所花费的时间来测定并进行计算的。反射信号使D触发器产生一个中断请求信号INT1,同时停止计数，读取计数值，经公式计算出实际距离，然后与基准距离进行比拟，如果检测的实际距离大于参考值80Cm时，不进行声光报警；如果有人靠近汽车进入驾驶室，检测的实际距离小于或等于参考值8
37、0cm时，通过单片机的P2.2和P2.3端口，驱动指示灯显示电路和声音报警电路，发出三声二闪光。并触发一个高电平，驱动无线信号发射电路。图1超声波发射电路1.2 编码/解码原理目前的汽车遥控防盗系统多是使用VD502627,PT226272,HT12E/D等通用的编码/解码电路，其密码由器件的地址来决定，每套防盗系统使用一个固定不变的密码。随着微处理技术的开展，通过接收遥控发射信号，就可以截获到这一固定的密码，而且一般的编解码器的地址输人端受器件尺寸限制，其数量不可能太多，能得到的不重复编码也就很有限，用自动扫描器也能很快破解密码。因此，这类密码固定不变的汽车防盗系统已受到严重的威胁。应用单片
38、机内部资源实现的跳变编码/解码汽车防盗系统，它每次使用的遥控密码都在变化，用过的密码不再重复使用，使得截获密码也是徒劳无功，此外，它可以增加足够多的密码位数，以提高系统抗击非法扫描的能力。遥控编码共有12个字节，分别由3字节编码通道码、3字节编码序号码,5字节跳变编码、1字节按键操作代码组成。在每个字节编码的前面加上一位逻辑O作为起始位，在每个字节编码的后面加上一位逻辑1作为停止位，并在最前面加上几位逻辑1作为引导信号，这就构成了用于发送的串行编码信号。编码通道用于表示遥控器的身份，每套系统使用一个固定的通道码。编码序号码于记录编码的次序，其初始值为O,单片机每编码一次，编码序号码就向上计数一
39、次。编码通道码和编码序号码存放在单片机的EEPROM中，确保它们不受停电影响。跳变编码是系统的真正密码，它由编码通道码和编码序号码经过复杂的特殊算法求出，该特殊算法对外保密。按键操作代码由被按的按键来决定，当设定键被按下时，其代码定为01H；当解除键被按下时，其代码定为OOH。解码是确认接收的编码是否合法的一系列操作过程。被确认合法的编码要满足三个条件；（1）编码通道码与解码通道码相同；（2）编码序号码大于解码序号码（解码序号码记录了上次合法使用过的编码序号码，该条件可保证以前使用过的编码无效）；（3）跳变码等于重新用特殊算法求出的变码。当单片机确认收到的是合法编码后，就把编码序号码写到解码序
40、号码中，并根据操作代码去完成相应的操作处理。解码通道码和解码序号码也存放在单片机的EEPROM中，以防因停电而丧失。1.3 防盗报警的实现假设有盗车者入室，发动汽车，输入错误的密码后，那么汽车电瓶的+12V电压，点火电流途经点火开关，点火电流中断，发动机熄灭，再启动，将重复上述过程，这样，盗贼始终不能将汽车开动，不能到达其预期目的。报警电路主要由集成块及扬声器和电子开关SCR组成。其中三极管或复合管，是为了提高功率而常采用的电路措施，它组成了一个电流放大倍数很大的等效晶体管，总放大倍数为这两管放大倍数的乘积。SCR是由可控硅构成的电子开关，电容和电阻构成降压器兼滤波器，给IC提供+3-+4V的
41、电压，IC为摸拟声报警集成电路，报警器由SCR控制，盗车贼一旦按错密码后，那么电瓶电流除一路进入防盗系统外，另一路是在发动机被启动，带动发动机工作后，其中性接点的输出电压，经微分电路，可控硅SCR被触发，又经电阻降压，电压加在IC的电源输入端，IC获得电压输出报警信号，经复合管放大，推动扬声器发出响亮的报警声。而在静态时，整个电路不耗电。2 .软件设计报警器软件设计主要分为：主程序（报警器初始化、健控和解码）；报警器中断处理程序。该报警器安装在汽车方向盘上。安装好后，启动报警器，报警器自动延迟2030s开始工作,以便让使用人有足够的时间锁好门离开汽车。延时后报警器进入值守工作状态，一旦车门被翻
42、开或窗玻璃被敲碎，振动传感器检测到信号，延时20s开始报警。延时的目的是使汽车的主人在开门进入车内能关闭报警器,以免误报警。图2主程序框架图2.1 主程序这一局部主要完成对各中断入口的设定，对各锁定单元和报警存放单元的初始化，设定特殊的标志值及对按键的中断处理。主程序设计框图如图2所示。2.2 报警器中断处理程序防盗报警器的处理程序采用时间中断查询处理，每一次时间中断，仅是去查询各种控制标志位，根据它的状态来控制各路输出。程序没有采用有循环处理的方式，所以控制未结束时，不能去除控制标志位，仅是复位现场，等待下一次时间中断，再判断是否控制结束03 .结语使用这种单片机组成的汽车防盗报警系统本钱低、性能可靠，同时安转方便。使用跳变码的编码/解码原理，使得系统更加平安，大大降低密码破解率，在未来的汽车防盗报警系统中将得到广泛的应用。
